Question with vectorisation?

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Manne Plok
Manne Plok 2018-9-6
编辑： Stephen23 2018-9-6
Hello This is the code I have.
n = 1:1000
A(n,1) = ceil(rand*5);
What this does is it finds a random value between 1 and 5, and places that same value in all rows 1 to 1000, col 1 of A. This is not what I wanted it to do. I wanted it to put a different random number each time for each row of A from 1 to 1000. I want to use vectorisation (and not for loops) because otherwise it is too slow. What step am I missing?

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回答（1 个）

Stephen23
Stephen23 2018-9-6
编辑：Stephen23 2018-9-6
Just use randi and define the output size:
A(1:1000,1) = randi(5,1000,1)
You could do the same with rand, but this is just more complex with no benefit:
A(1:1000,1) = ceil(5*rand(1000,1))

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